Ganglioside metabolism will be correlated with structure and function in the hippocampus under precisely defined conditions of development change and experimentally induced plasticity. The four phases of this study will consist of: (1) Determination of optimal methods for microanalysis of ganglioside metabolism in minute tissue samples; (2) Correlation of changes in ganglioside metabolism with precise morphogenetic events during the normal development of individual subfields of the hippocampus; (3) Correlation of changes in ganglioside metabolism with structural plasticity in the hippocampus, experimentally induced by kainic acid and thyroxin; and (4) Correlation of changes in ganglioside metabolism with physiological modulation, experimentally induced by corticosterone stimulation and noradrenergic denervation.